[chrony-users] GPS + PPS

[Dominik Auras <wohnung.elisabethstrasse@xxxxxxxxx>]

Hello!

I am trying to setup chrony for my new GPS. Unfortunately, chrony won't select any source if I enable both the NMEA and PPS source. I bet that my configuration is wrong ... but it is unclear to me how to configure the PPS.

Could you maybe explain me what I do wrong, or point me to something that explains it? Thank you in advance!

Part of my chrony.conf

server ptbtime1.ptb.de iburst noselect maxpoll 6 minpoll 6
refclock SHM 0 refid GPS offset 0.546 poll 6 delay 0.9999
refclock SHM 1 delay 0.2 refid PPS lock GPS
minsamples 64
makestep 1000 -1

Output of chronyc sources:

210 Number of sources = 3
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
#x GPS                           0   6   377    82   -21.0s[ -21.0s] +/-  503ms
#x PPS                           0   4   377    22    +16ms[  +16ms] +/-  100ms
^x ptbtime1.ptb.de               1   6   377    46   -21.0s[ -21.0s] +/-   30ms

Output of chronyc sourcestats

210 Number of sources = 3
Name/IP Address            NP  NR  Span  Frequency  Freq Skew  Offset  Std Dev
==============================================================================
GPS                        64  21   67m     -0.646      4.511   -21.0s    11ms
PPS                        64  23  1009      3.062      0.006    +16ms  3620ns
ptbtime1.ptb.de            64  33   69m      2.952      0.191   -21.0s   498us

The PPS is the rpi_gpio_ntp program running in the background.

chrony won't have internet access once it is deployed ...

BR, Dominik